"Vigil Strange” is technically a free verse poem—Whitman’s specialty—through many of the lines are scannable. The opening line, “Vigil strange I kept on the field one night” (Line 1), is trochaic pentameter: meter consisting of five stressed syllables in a line on which the first syllable receives the emphasis (this is the opposite of the more familiar iambic pentameter of Shakespearean verse).

Following this, Whitman offers a line in hexameter—six metrical feet in a line—and two lines of heptameter, or seven feet in a line. His refusal to conform and adhere to a singular poetic meter highlights the unique and distinctive nature of Whitman’s poetry. In “Vigil Strange,” the accumulating stresses in the opening of the poem is a technique found in other Whitman poems. The line lengths and stressed versus unstressed syllables in the lines are all quite deliberate choices—even though, upon first reading or an unfamiliarity with Whitman’s poetry, this may seem messy or confusing.

This poem is noteworthy for Whitman’s inverted syntax. Even the title, repeated as the first line, inverts the expected word order. Instead of calling the poem “I Kept a Strange Vigil on the Field one Night,” Whitman reorders the line to emphasize both the disorientation of war and to focus readers’ attention on the poem’s keyword: “vigil.